1. Field of the Invention
The present invention relates to a backlight unit, more particularly, to a multi-angle reflector for use in a backlight unit.
2. Description of the Related Art
Referring to FIG. 1, according to Japan Patent Publication No. 05-323312, the conventional backlight unit 1 comprises a plurality of lamps 11, a diffuser 12 and a reflector 13. The backlight unit 1 is disposed under a liquid crystal panel in the liquid crystal display device. The lamps 11, which can be fluorescent lamps, are used for providing light source. The diffuser 12, used in diffusing the light emitted from the lamps 11 to the liquid crystal panel, is placed above the lamps 11, and the material of the diffuser 12 is usually polymethymetharylate (PMMA) or polycarbonate (PC). The reflector 13, which is made of reflecting polycarbonate or polyethylene terephthalate (PET), is disposed under the lamps 11 for used for reflecting the bottom light source emitted from the backlight unit 1 to the diffuser 12.
Because the lamps 11 are disposed directly under the diffuser 12, the brightness is high in the direct under type of backlight unit 1. Furthermore, its weight is lighter than other types of backlight unit by the simple structure. In addition, when users look at the monitors, they will feel the view angles larger because there are no shelters above the diffuser 12 in the direct under type of backlight unit 1. On the other hand, the regions directly above the lamps 11 are brighter because the light emits directly onto the diffuser 12 while the regions between the lamps are darker. Thus, the lights are not uniform. Besides, enough space should be kept between the lamps 11 and the diffuser 12 in the direct under type of backlight unit 1 to avoid being over bright in view of that the lamps 11 emit light to the diffuser 12 directly. Therefore, compared with other types of backlight unit, the direct under type is thicker.
Besides, because the conventional reflector 13 is integrally made, the reflecting angles and the distance between the reflector 13 and lamps 11 are fixed. The reflecting angles of the reflector 13 cannot be adjusted according to the brightness, the number of the lamps 11 and the distance between the reflector 13 and lamps 11. The lights reflected to the diffuser 12 are not uniform.
Therefore, it is necessary to provide an innovative and progressive multi-angle reflector so as to solve the above problem.
One objective of the present invention is to provide a multi-angle reflector for use in a backlight unit. The backlight unit comprises a plurality of lamps, a reflector and a diffuser. The diffuser is disposed above the lamps. The multi-angle reflector is disposed under the lamps. The reflector with a plurality of reflection angles comprises a plate and a plurality of reflecting protrusions. The plate has a top surface facing the lamps. The reflecting protrusions are respectively disposed on the top surface of the plate. Each reflecting protrusion has a reflecting surface. The reflecting surfaces have respective reflecting angles corresponding to the top surface of the plate so that the lights from lamps are adapted to reflect to the diffuser according to the reflecting angles.
Therefore, according to the invention, the reflecting angles of the reflecting surfaces on the reflecting protrusions can be adjusted so as to suit to the number of lamps and the distance between lamps and the reflector. The lights are reflected to the diffuser by various reflecting angles, and the lights are uniform and the utility of the lights is improved. Because the reflecting protrusions are small, the reflector can be made into a thin type. For the whole structure, the thickness of the backlight unit is decreased.